Stabilized miniaturized housed reed vibrator



y 9, 1967 KAZUO YAKUWA ETAL 3,319,197

STABILIZED MINIATUHIZED HOUSED REED VIBRATOR Filed Nov. 18, 1964 United States Patent Ofiiice 3,319,197 Patented May 9, 1967 The present invention relates to a reed vibrator. More particularly, the invention relates to a reed vibrator provided with stabilized characteristics and miniaturized construction. I

The reed vibrator, as commonly known, is composed of a vibrator, which vibrates at the resonant frequency, and a drive system, which includes a permanent magnet and a driving coil. The driving coil actuates the vibrator. The reed vibrator may be so positioned and constructed that the contact points are in the free end of the vibrator and its corresponding position. If an electric current having a frequency which is exactly the same as the resonant frequency of the vibrator is supplied to the drive system, a resonant movement arises in the vibrator and provides an operation of intermittent make and break between both contact points at the resonance frequency. This results in the selective control of the other circuit through the intermittent contact operation. The vibrator may be used, for example, as the signal selective element in a selective calling device for vehicle-carried radio-telephone use.

If the drive system is positioned in one of the arms of a bridge circuit and is supplied with a current having a frequency which is the same as the resonant frequency of the vibrator of the reed vibrator, unbalance of the bridge enables the unbalanced current, the frequency of which is the same as that at vibrator resonance, to appear at the bridge output. The unbalanced current may thus be used for the same purpose as the aforedescribcd reed vibrato-r without the need for a contact point.

It is an object of the invention to provide a reed vibrator which operates only at a particularly determined frequency of current and is thus used for the selective control operation of other circuits, and which is of structure which is small in size and of high performance.

In accordance with the present invention, the drive system, which comprises the permanent magnet and the driving coil, is arranged in the internal air space of the vibrator. The vibrator is of substantially U-shaped configuration and one end of the drive system is secured to the base part of the U-shaped vibrator. The construction and arrangement of the present invention permits the attainment of a great degree of miniaturization and great improvement in performance.

In order that the present invention may be readily carried into effect, it will now be described with reference to the accompanying drawings, wherein:

FIG. 1 is a front plan of an embodiment of the reed vibrator of the present invention; and

FIG. 2 is an exploded perspective view of the embodiment of FIG. 1.

In the figures, the same components are indicated by the same reference numerals.

A principal support member 11 is of substantially C- shaped configuration and may be made of any suitable material such as, for example, aluminum or other metal. If the support member 11 is metal, its surface is coated with insulation; the surface of aluminum being treated by anodized oxidation to provide a film of insulation. The film of insulation enables the support member 11 to be directly mounted without the need for other insulation material, as heretofore required.

A vibrator 12 is of substantially U-shaped configuration. The vibrator 12 comprises a substantially rectangular base part 13 in the shape of an elongated plate having a hole 14 formed therethrough, a substantially rectangular first arm part 15 in the shape of an elongated plate extending at substantially right angles from one end edge of the base part 13, and a substantially rectan, gula-r second arm part 16 in the shape of an elongated plate extending at substantially right angles from the other end edge of the base part 13. A weight 17 is affixed to the outside surface of the first arm 15 near the end edge of said arm and functions also as a contact element. A weight 18 is aifixed to the outside surface of the second arm 16 near the end edge of said arm and functions also as a contact element. The weights 17 and 18 are utilized for frequency adjustment as well as for contact purposes.

When supported in operating position in the reed vi.- brato-r of the present invention, the vibrator 12 is positioned with its base part 13 substantially horizontal and its arm parts 15 and 16 substantially vertical and extending downward. The vibrator 12 may, of course, be positioned otherwise as long as the relationship of its components and those of the device remain operative.

A non-magnetic plate 19, which may comprise a metal plate, is afiixed to the top surface of the base part 13 by any suitable means such as, for example, by solder. A non-magnetic plate 21, which may comprise a metal plate, is affixed to the bottom surface of the base part 13 by any suitable means such as, for example, by solder. A permanent magnet 22, which forms part of the drive system, is affixed to the bottom surface of the plate 21 'by any suitable means. The permanent magnet 22, as well as the plate 21, are thus positioned in the internal space formed by the vibrator 12.

An iron yoke 23 is afiixed to the bottom surface of the magnet 22 by any suitable means. A drive coil 24 is wound about the iron yoke 23. The iron yoke 23 is of substantially T-shaped configuration and is positioned in inverted arrangement. The iron yoke 23 is preferably made of magnetic material such as, for example, pure iron, permalloy or the like and comprises a stem part 25 of substantially cylindrical configuration and a first head part 26 of substantially disc configuration affixed to one end of the stem part 25. The first head part 26 is preferably of magnetic material.

A second head part 27 of substantially disc configuration having a hole 28 formed therethrough is preferably made of non-magnetic material such as, for example, nonmagnetic metal. The other end of the stem part 25 is inserted in the hole 28 and the second head part 27 is affixed to the said other end of said stem part. The drive system, comprising the components 21, 22, 23, 24, 25, 26 and 27, is thus positioned wholly in the space formed by the vibrator 12 between the base part 13 and the first and second arm parts 15 and 16.

The yoke 23 thus comprises substantially parallel flanges 26 and 27 on the stem part 25 which flanges are substantially perpendicular to said stem part. The non-magnetic second head part 27 is affixed to the bottom surface of the permanent magnet 22 by any suitable means. The stem part 25 is preferably coated with insulation material which may be pointed as a film and the bottom surface of the second head part 27 and the top surface of the first head part 26 are preferably similarly coated. This enables the direct winding of the drive coil 24 on the stem part 25.

The vibrator 12, with the drive system affixed to it in the space defined by its base part 13 and its first and second arms 15 and 16, as hereinbefore described, is mounted, in the space defined by the support member 11, to said support member. The vibrator 12 may be r, 3 mounted on the support member 11 by any suitable means i such as, for example, a screw 29 which may be threadedly coupled to an internally threaded aperture formed in the plate 21.

The reed vibrator of the present invention, comprising the substantially U-shaped vibrator and the drive system, is thus constructed and arranged in such a way, as hereinbefore described, as to enable the manufacture of a reed selector which is small in size. A contact member 31 is positioned in operative proximity with the weight or contact 17 affixed to the outside surface of the first arm of the vibrator 12.

The contact member 31 may comprise a short length of wire or other suitable electrically conductive material. The contact member 31 is supported at one end by a support spring 32. The support spring 32 is bent at substantially right angles in its top portion to provide a substantially horizontal leg or part 33. The leg or part 33 of the support spring 32 has a hole 34 formed through it. The angle part of the support spring 32 formed by the substantially horizontal part 33 and the remainder of said support spring has a substantially narrow slot or slit 35 formed therethrough and extending into both legs of said support spring.

The top end 36 of the contact member 31 is supported in the slot 35 of the support spring 32. The substantially vertical leg or part 37 of the support spring 32 is bent twice at right angles in its central portion to provide a transverse part 38 which forms an obtuse angle with each of the two bounding portions of the substantially vertical part 37. The angles formed by the transverse part 38 and the bounding portions of the substantially vertical part 37 are 39 and 41, respectively. The contact member 31 abuts the substantially vertical leg 37 of the support spring 32 at the angle 41 of said leg.

The support spring 32 is bent at substantially right angles in its bottom portion to provide a substantially horizontal catch or hook portion 42 in which the bottom end 43 of the contact member 31 is held.

The support spring 32 is fastened to the support member 11 by any suitable means such as, for example, a rivet or bolt 44 which is passed through the hole 34 formed through the part 33 of said support spring and through a hole 45 formed through said support member.

A groove or notch 46 is formed in the edge of the substantially horizontal top part 47 of the support member 11. A substantially vertical side part 48 of the support member 11 extends substantially perpendicularly to the substantially vertical principal part 49 of said support member and to the top part 47 of said support member. An internally threaded hole 51 is formed through the side part 48 of the support member 11. A screw or threaded member 52 is positioned in the hole 51 in threaded engagement therewith.

The support spring 32 is positioned with its part 33 fastened to the top part 47 of the support member 11, with its upper angular portion in the notch 46 of the top part 47 of said support member, and with its part 37 abutting against the inside of the part 48 of said support member. The screw 52 contacts the part'37 of the support spring 32, so that movement of said screw varies the position of said support spring. The structure and arrangement of the support spring 32 and the contact member 31 enables the attainment of any degree of adjustment for the spacing of the contact of said contact member and the contact 17, by the turning of the screw 52.

When a current of a determined frequency flows through the drive coil 24, a magnetic flux is produced which alternates at the determined frequency. The magnetic flux passes through the magnetic circuit, together with the DC. magnetic flux of the permanent magnet 22. The magnetic circuit comprises the yoke 23, the permanent magnet 22, the non-magnetic metal plate 21 and the vibrator 12. The driving force, which varies at the same frequency as that of the alternating current supplied to the drive coil 24, is applied to the vibrator 12. The driving force drives the vibrator 12 into forced oscillation, and when the driving frequency, which is the frequency of the current supplied to the drive coil 24,'coincides with the resonant frequency of the vibrator 12, the amplitude of the oscillation becomes a maximum, causing an intermittent open and close or non-contact and contact operation of the contact 17 and the contact member 31. The intermittent operation of the contact 17 and the contact member 31 is utilized to selectively control another circuit.

As mentioned, the substantially U-shaped configuration of the vibrator 12 and the positioning of the drive system in the internal space of said vibrator between the base part 13 and the first and second arm parts 15 and 16 thereof, results in the most efficient use of the air space in the construction of the reed vibrator, and the overall size and total dimensions may consequently be made extremely small without shortening the length of the vibrating element or vibrator.

The drive system, which is aflixed to the base part 13 of the vibrator 12 in symmetry in accordance with the 7 center line of the drive system, is considered the same as a system having two vibrators of L-shaped configuration and the oscillation is produced theoretically in the same manner of operation as the vibrating element of a tuning fork. Therefore, as compared with the conventional vibrating element of cantilever type, a higher lever of Q and double tuning characteristics may be provided, with the further advantage of easy manufacture. Consequently, economical production is possible at considerably less cost than the conventional tuning fork manufactured by hitherto known methods.

As herein before described, the symmetrical construction of the vibrator or vibrating element in accordance with the center line of the drive system produces an alternating magnetic flux in the air gap between the left and right arms or the first and second arm parts of the vibrator and the yoke superposed with a DC. magnetic flux of the permanent magnet and results in an attracting force alternating at a given frequency, when A.C. current is supplied to the drive coil at the given frequency. That is, the same magnitude of force is applied to the first arm part 15 of the vibrator 12 as to the second arm part 16 thereof to attract either of said arm parts and the same magnitude of force is applied to said first arm part as to said second arm part to repel either of said arm parts. The left and right or first and second arms of the vibrator may be made to vibrate at the same phase with the same amount of energy. Accordingly, the motion of each of the first and second arms cancels in the other the force of movement to obtain energy balance. This reduces the reaction on the support member 11 to an extremely small magnitude as compared with a cantilever vibrator.

The support structure of the vibrating element of a conventional cantilever requires a length, in the direction of the vibrator length, which is one half to one third the vibrator length. The support structure of the present invention, however, requires a length, in the direction of the vibrator length, which is less than one fifth the vibrator length, thus permitting the support structure to provide a stabilized performance.

The reed vibrator of the present invention utilizes the non-magnetic metal plate 21 to affix the drive system to the vibrator or vibrating elements 12, which plate thus functions as an effective air gap in the magnetic circuit to enable the frequency to increase its stability. The larger the value of the negative stiffness, the lower the frequency of the vibrator. The amount of the negative stiffness is inversely proportional to the third power of the magnitude of the effective air gap of the magnetic circuit. Thus, if the value of negative stiffness is larger when the effective air gap is smaller, the frequency and sensitivity of the vibrator change considerably even for a slight variation in the air gap length between the v-ibra,-

tor and the yoke when said vibrator is vibrating. However, as hereinbefore described, the intermediate positioning of the non-magnetic metal plate 21 in the magnetic circuit to enlarge the effective air gap of the magnetic circuit enables the frequency of vibration to improve its stability without actually widening the air gap clearance between the vibrator and the yoke; that is, without enlarging the overall dimensions or total size.

Another advantage of the present invention is that due to the structure of the yoke of the drive system and of the magnetic and non-magnetic components thereof and due to the directly wound drive coil on the stem part 25 of the yoke 23 and the insulation material on said stem part, the components may be of very small size and the drive coil may be wound at high speed.

The reed selector of the present invention may be made of small size due to the structure and arrangement of the contact member 31 and the support spring 32 and due to their mounting in the reed vibrator. Furthermore, the slot 35 of the support spring 32 enables the maintenance of substantially constant pressure between the angle 41 of said support spring and the contact member 31 as said support spring is displaced by the screw 52. This prevents a decrease in contact efiiciency and also prevents chattering. The prevention of a decrease in contact eificiency and the prevention of chattering achieved by variation of the contact pressure between the support spring 32 and the member 31, and the adjustment of the spacing of the contact member 31 achieved by the displacement of the support spring 32, are accomplished independently and permit adjustment of the device of the present invention with little effort.

While the invention has been described by means of a specific example and in a specific embodiment, we do not wish to be limited thereto, for obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the invention.

We claim:

1. A reed vibrator, comprising a vibrator of substantially U-shaped configuration having a base part, a first arm part extending from one end of said base part and a second arm part extending from the other end of said base part; support means supporting said vibrator; and

drive means for vibrating said vibrator afiixed to the base part of said vibrator and positioned in the space formed by the said base part, the first arm part and the second arm part of said vibrator, said drive means comprising a yoke, a coil wound on said yoke, a permanent magnet positioned between the base part of said vibrator and said yoke and a non-magnetic plate positioned between said permanent magnet and v the base part of said vibrator.

2. A reed vibrator, comprising a vibrator of substantially U-shaped configuration having a base part, a first arm part extending from one end of said base part and a second arm part extending from the other end of said base part;

support means supporting said vibrator; and

drive means for vibrating said vibrator aflixed to the base part of said vibrator and positioned in the space formed by the said base part, the first arm part and the second arm part of said vibrator, said drive means comprising a yoke having a magnetic stem part having a coat of insulating material, a coil wound on the stem part of said yoke, a permanent magnet positioned between the base part of said vibrator and said yoke and a non-magnetic plate positioned between said permanent magnet and the base part of said vibrator.

'3. A reed vibrator, comprising a vibrator of substantially U-shaped configuration having a base part, a first arm part extending from one end of said base part and a second arm part extending from the other end of said base part;

support means supporting said vibrator; and

drive means for vibrating said vibrator affixed to the base part of said vibrator and positioned in the space formed by the said base part, the first arm part and the second arm part of said vibrator, said drive means comprising a yoke having a magnetic stem part having a coating of insulating material thereon, a first head part of magnetic material of substantially disc configuration afiixed to one end of said stem part and a second head part of nonmagnetic material of substantially disc configuration afiixed to the other end of said stem part, said first and second head parts being substantially perpendicular to said stem part and substantially parallel to each other, said drive means further comprising a coil wound on the stem part of said yoke, a permanent magnet positioned betwen the base part of said vibrator and the second head part of said yoke and a non-magnetic plate positioned between said permanent magnet and the base part of said vibrator.

4. A reed vibrator, comprising a vibrator of substantially U-shaped configuration having a base part, a first arm part extending from one end of said base part and a second arm part extending from the other end of said base part;

support rneans supporting said vibrator;

drive means for vibrating said vibrator affixedto the base part of said vibrator and positioned in the space formed by the said base part, the first arm part and the second arm part of said vibrator, said drive means comprising a yoke, a coil wound on said yoke, a permanent magnet positioned between the base part of said vibrator and said yoke and a nonmagnetic plate positioned between said permanent magnet and the base part of said vibrator;

contact means on the first arm part of said vibrator in the area of the end thereof farthest from the base part of said vibrator;

support spring means of substantially strip configuration bent at angles to itself in its top, bottom and central areas, said support spring means being supported at its top area by said support means and having a substantially narrow slot formed therethrough in its top area; and

contact member means of substantially wire configuration having a top end supported by said support spring means in the slot thereof, a bottom end held by said support spring means at its bottom area and a central area abutting said support spring means at an angle formed in the central area thereof, said contact member means being supported by said support spring means in operative proximity with the contact means on the first arm part of said vibrator.

5. A reed vibrator, comprising a vibrator of substantially U-shaped configuration having a base part, a first arm part extending from one end of said base part and a second arm part extending from the other end of said base part;

support means supporting said vibrator;

drive means for vibrating said vibrator afiixedto the base part of said vibrator and positioned in the space formed by the said base part, the first arm part and the second arm part of said vibrator,

said drive means comprising a yoke having a magnetic stem part having a coating of insulating material thereon, a first head part of magnetic material of substantially disc configuration afiixed to one end of said stem part and a second head part of nonmagnetic material of substantially disc configuration afiixed to the other end of said stem part, said first and second head parts being substantially perpendicular to said stem part and substantially parallel to each other, said drive means further comprising 7 a coil wound on the stern part of said yoke, 21 permanent magnet positioned between the base part of said vibrator and the second head part of said yoke and a non-magnetic plate positioned between said permanent magnet and the base part of said vibrator;

contact means on the first arm part of said vibrator in the area of the end thereof farthest from the base part of said vibrator;

support spring means of substantially strip configuration bent at angles to itself in its top, bottom and central areas, said support spring means being supported at its top area by said support means and having a substantially narrow slot formed therethrough in its top area; and

contact member means of substantially wire configuration having a top end supported by said support spring means in the slot thereof, a bottom end held by said support spring means at its bottom area and a central area abutting said support spring means at an angle formed in the central area thereof, said contact member means being supported by said support spring means in operative proximity with the contact means on the first arm part of said vibrator.

A reed vibrator, comprising a vibrator of substantially U-shaped configuration having a base part, a first arm part extending from one end of said base part substantially perpendicularly thereto and a second arm part extending from the other end of said base part substantially perpendicularly thereto and substantially parallel to said first arm part, each of said base part, said first arm part and said second arm part being of substantially rectangular configuration;

support means supporting said vibrator; and drive means for vibrating said vibrator afiixed to substantially the center of the base part of said vibrator and positioned in the space formed by the said base part, the first arm part and the second arm part of said vibrator, said drive means comprising a yoke, a coil wound on said yoke, a permanent magnet positioned between the base part of said vibrator and said yoke and a non-magnetic plate positioned between said permanent magnet and the base part of said vibrator.

A reed vibrator, comprising a vibrator of substantially U-shaped configuration having a base part, a first arm part extending from one end of said base part substantially perpendicularly thereto and a second arm part extending from the other end of said base part substantially perpendicularly thereto and substantially parallel to said first arm part, each of said base part, said first arm part and said second arm part being of substantially rectangular configuration;

support means supporting said vibrator; and I drive means for vibrating said vibrator affixed to suba vibrator of substantially U-shaped configuration having a base part, a first arm part extending from one end of said base part substantially perpendicularly thereto and a second arm part extending from the other end of said base part substantially perpendicularly thereto and substantially parallel to said first arm part, each of said base part, said first arm part and said second arm part being of substantially rectangular configuration;

support means supporting said vibrator; and

drive means for vibrating said vibrator affixed to substantially the center of the base part of said vibrator and positioned in the space formed by the said base part, the first arm part and the second arm part of said vibrator, said drive means comprising a yoke having a magnetic stern part having a coating of insulating material thereon, a first head part of magnetic material of substantially disc configuration aifixed to one end of said stem part and a second head part of non-magnetic material of substantially disc configuration aflixed to the other end of said stem part, said first and second head parts being substantially perpendicular to said stem part and substantially parallel to each other, Said drive means further comprising a coil wound on the stem part of said yoke, a permanent magnet positioned between the base part of said vibrator and the second head 7 part of said yoke and a non-magnetic plate positioned between said permanent magnet and the base part of said vibrator.

9. A reed vibrator, comprising a vibrator of substantially U-shaped configuration having a base part, a first arm part extending from one end of said base part substantially perpendicularly thereto and a second arm part extending from the other end of said base part substantially perpendicularly thereto and substantially parallel to said first arm part, each of said base part, said first arm part and said second arm part being of substantially rectangular configuration;

support means supporting said vibrator;

drive means for vibrating said vibrator affixed to substantially the center of the base part of said vibrator and positioned in the space formed by the said base part, the first arm part and the second arm part of said vibrator, said drive means comprising a yoke, a coil wound on said yoke, a permanent magnet positioned between the base part of said vibrator and said yoke and a non-magnetic plate positioned between said permanent magnet and the base part of said vibrator;

contact means on the first arm part of said vibrator in the area of the end thereof farthest from the base part of said vibrator;

support spring means of substantially strip configuration bent at angles to itself in its top, bottom and central areas, said support spring means being supported at its top area by said support means and having a substantially narrow slot formed therethrough in its top area; and

contact member means of substantially wire configuration having a top end supported by said support spring means in the slot thereof, a bottom end held by said support spring means at its bottom area and a central area abutting said support spring means at an angle formed in the central area thereof, said contact member means being supported by said support spring means in operative proximity with the contact means on the first arm part of said vibrator.

10. A reed vibrator, comprising a vibrator of substantially U-shaped configuration having a base part, a first arm part extending from one end of said base part substantially perpendicularly thereto and a second arm part extending from the other end of said base part substantially perpendicularly thereto and substantially parallel to said first arm part, each of said base part, said first arm part and said second arm part being of substantially rectangular configuration;

support means supporting said vibrator;

drive means for vibrating said vibrator aflixed to substantially the center of the base part of said vibrator and positioned in the space formed by the said base part, the first arm part and the second arm part of said vibrator, said drive means comprising a yoke having a magnetic stem part having a coating of insulating material thereon, a first head part of magnetic material of substantially disc-configuration aflixed to one end of said stem part and a second head part of non-magnetic material of substantially disc configuration afiixed to the other end of said stem part, said first and second head parts being substantially percontact member means of substantially wire configura tion having a top end supported :by said support spring means in the slot thereof, a bottom end held by said support spring means at its bottom area and a central area abutting said support spring means at an angle formed in the central area thereof, said conpendicular to said stern part and substantially parallel l0 t t be means being supported by said support to each other, said drive means further comprising a spring means in operative proximity with th Coil wound on The Stem P of Said yoke, 21 P tact means on the first arm part of said vibrator.

nent magnet positioned between the base part of said vibrator and the second head part of said yoke and 15 References Cited by the Examiner a non-magnetic plate positioned between said perma- UNITED STATES PATENTS nent magnet and the base part of said vibrator; contact means on the first arm part of said vibrator in the area of the end thereof farthest from the base part of said vibrator; support spring means of substantially strip configuration bent at angles to itself in its top, bottom and central 2,872,598 2/1959 Birkemeicr 31025 20 BERNARD A. GILHEANY, Primary Examiner.

R. N. ENVALL, Assistant Examiner. 

1. A REED VIBRATOR, COMPRISING A VIBRATOR OF SUBSTANTIALLY U-SHAPED CONFIGURATION HAVING A BASE PART, A FIRST ARM PART EXTENDING FROM ONE END OF SAID BASE PART AND A SECOND ARM PART EXTENDING FROM THE OTHER END OF SAID BASE PART; SUPPORT MEANS SUPPORTING SAID VIBRATOR; AND DRIVE MEANS FOR VIBRATING SAID VIBRATOR AFFIXED TO THE BASE PART OF SAID VIBRATOR AND POSITIONED IN THE SPACE FORMED BY THE SAID BASE PART, THE FIRST ARM PART AND THE SECOND ARM PART OF SAID VIBRATOR, SAID DRIVE MEANS COMPRISING A YOKE, A COIL WOUND ON SAID YOKE, A PERMANENT MAGNET POSITIONED BETWEEN THE BASE PART OF SAID VIBRATOR AND SAID YOKE AND A NON-MAGNETIC PLATE POSITIONED BETWEEN SAID PERMANENT MAGNET AND THE BASE PART OF SAID VIBRATOR. 